1. Field of the Invention
The present invention relates to a portable electronic apparatus with an improved operability, and more particularly to a hand-held portable electronic apparatus including a protruding holding unit that can be operated by a same hand holding the portable electronic apparatus.
2. Description of the Related Art
It is known electronic apparatuses (such as a portable computer, a portable word processor, various types of portable electronic terminal apparatuses, etc.) are configured so various operations can be performed by operating a pointing device and switches of the apparatus with fingers of one hand holding the apparatuses. These apparatuses are conveniently configured to be operated by only one hand holding the apparatus when a user is in, for example, a crowded train or when the user holds a bag with the other hand, and so on.
For example, a portable information processing apparatus having a rectangular plate shape and a thickness suitable for holding it with one hand (e.g., with the left hand) is described in Japanese Patent Laid-Open Publication No. 10-20964. This known apparatus includes an LCD display and a pointing device, which is operable only with a thumb of the left hand. Accordingly, the pointing device is located at an appropriate place on a left side edge of the LCD display. Also included on the back side of the apparatus is an instruction switch for setting a position designated on the LCD display by the pointing device or to cancel the designation. The instruction switch can be operated with the fingers of the left hand other than the thumb.
The known portable information processing apparatus is held at the edge of the rectangular plate-shaped body with the thumb and other fingers of one hand. The pointing device is operated with fingers of the same hand holding the apparatus. When the pointing device or the instruction switch is operated with respective fingers of the hand holding the apparatus, the apparatus shakes or sways, making it difficult to operate. This results in misoperations. When the pointing device is operated with the thumb, the apparatus especially tends to sway due to changes in the positions where respective forces of the other fingers are exerted.
Because the apparatus is held at its surface and backside by the thumb and other fingers, respectively, the operation of the pointing device (e.g., moving a cursor on the display) must be performed by exerting an extra force on the pointing device with the thumb (i.e., to offset the intensity of forces of the other fingers holding the apparatus). However, the thumb tends to slip over the pointing device when the force exerted on the pointing device by the thumb is increased. When the thumb slips over the pointing device and drops from the surface of the apparatus or accidently moves to an edge of the apparatus (where it is hard to exert pressure with the thumb), the apparatus may slip out of the user's hand, fall to the ground and be damaged.